In general, a washing machine washes laundry by using friction between water and laundry where the friction is caused by a rotation of a pulsator installed in a washing tub. Specifically, a plurality of holes is formed in an outer circumferential surface of the washing tub which is positioned inside of the tub, such that water introduced into the tub is also introduced into the washing tub and water in the washing tub is discharged into the tub for eventual discharge to a drain line. That is, during the processes of a washing process, a rinsing process, and a spin-drying process, the water in the tub is discharged to the outside of the tub through a drain line installed at a lower side of the tub.
Therefore, the laundry accommodated in the washing tub is washed by the rotation of the pulsator, the rotation of the washing water stored in the tub, and the washing tub, and contact between the water and the laundry.
However, when detergent or foreign substances which may remain on surfaces of the laundry are left on the laundry when worn, dermatitis (such as atopic dermatitis) may be caused when a user repeatedly wears the clothes.
To prevent this problem, various technologies for supplying small amounts of washing water to the surfaces of the laundry are applied, but there is a problem in that a separate device needs to be installed, such as a pump for creating the small amounts of washing water. In this case, there are problems due to noise associated with the operation of the pump and there is difficulty regarding the maintenance of the pump over time when the pump is repeatedly used.
In the case in which the washing water remains in certain devices required for supplying the small amounts of washing water during winter, for instance, there is a problem in that these devices may become frozen.